# Where is full vs limited range recorded in a file (MP4 nclx, MOV nclc, H.264/HEVC VUI, codec atoms), and what goes wrong when it is wrong?

- id: art_01M5MCCPB9YKH2XBT1TA92SSTZ
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T06, T10, T12 · tags: none
- updated: 2026-10-23T12:39:51.906Z
- url: https://veyrul.com/articles/art_01M5MCCPB9YKH2XBT1TA92SSTZ

Range can live in several places. In FFmpeg movenc.c (pin 9047fa1b) MP4/AVIF colr nclx has a range bit, while MOV colr nclc has none; the H.264/HEVC bitstream filters set video_full_range_flag in VUI; DNxHD in MOV gets a separate ACLR atom with a full/legal range marker. Filters (setparams, scale) can mark or convert range. A practitioner says Rec.709 should never be full range and reports crushed/clipped results when it is; BT.709-6 as read defines 219/224 quantisation but the word "full range" does not occur in its text (searched, two spellings).

Range can live in several places. In FFmpeg movenc.c (pin 9047fa1b) MP4/AVIF colr nclx has a range bit, while MOV colr nclc has none; the H.264/HEVC bitstream filters set video_full_range_flag in VUI; DNxHD in MOV gets a separate ACLR atom with a full/legal range marker. Filters (setparams, scale) can mark or convert range. A practitioner says Rec.709 should never be full range and reports crushed/clipped results when it is; BT.709-6 as read defines 219/224 quantisation but the word "full range" does not occur in its text (searched, two spellings).

Curator qualifications: Range lives in different places by container: nclx range bit (MP4/AVIF), none in MOV nclc, VUI video_full_range_flag via bitstream filters, ACLR for DNxHD in MOV.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/9047fa1b084f76b1b4d065af2d743df1b40dfb56/libavformat/movenc.c",
      "note": "FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/9047fa1b084f76b1b4d065af2d743df1b40dfb56/doc/bitstream_filters.texi",
      "note": "FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/9047fa1b084f76b1b4d065af2d743df1b40dfb56/doc/filters.texi",
      "note": "FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/9047fa1b084f76b1b4d065af2d743df1b40dfb56/libavutil/pixfmt.h",
      "note": "FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623"
    },
    {
      "url": "https://community.adobe.com/questions-729/color-issue-after-exporting-in-different-viewing-softwares-1621842",
      "note": "FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623"
    },
    {
      "url": "https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.709-6-201506-I!!PDF-E.pdf",
      "note": "FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623"
    },
    {
      "url": "https://github.com/chromium/chromium/blob/44e7da44a3c620bfdc331971bf64cd2364ddc4c9/media/base/video_color_space.cc",
      "note": "FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] Range can live in several places. In FFmpeg movenc.c (pin 9047fa1b) MP4/AVIF colr nclx has a range bit, while MOV colr nclc has none; the H.264/HEVC bitstream filters set video_full_range_flag in VUI; DNxHD in MOV gets a separate ACLR atom with a full/legal range marker. Filters (setparams, scale) can mark or convert range. A practitioner says Rec.709 should never be full range and reports crushed/clipped results when it is; BT.709-6 as read defines 219/224 quantisation but the word "full range" does not occur in its text (searched, two spellings). · locator: FFmpeg 9047fa1b libavformat/movenc.c L1744-L1752, L2608-L2623 · source: https://github.com/FFmpeg/FFmpeg/blob/9047fa1b084f76b1b4d065af2d743df1b40dfb56/libavformat/movenc.c

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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